In the fields of clinical medicine and the like, sample analysis devices that are disposed of after being used once are used widely for fluid samples, for instance, body fluids such as blood, urine, and spinal fluid. In a sample analysis device composed of a porous sheet made of filter paper, a plastic film, etc., a sample such as blood is spotted on a part of the porous sheet, and it is spread through the inside of the porous sheet due to the capillary phenomenon. In the case where the sample is whole blood, blood cells are separated from blood plasma and blood serum due to the chromatography effect while the whole blood is being spread through the inside. The sample analysis device in which the sample is thus spread can be used, as it is, for holding the sample or for preserving the sample. Further, it is possible that, after a certain period of time elapses from the sampling of the sample, the porous sheet is removed out of the sample analysis device and a certain target component such as blood plasma, blood serum, etc. is extracted therefrom so that the extracted component is subjected to analysis. Further, in the case where an analytical reagent, etc. further is held in the porous sheet, the reagent and the component of the sample thus spread can be reacted with each other in the sample analysis device. Therefore, it is possible to observe the reaction directly in the sample analysis device by visual observation, and to analyze the reaction by an optical means or an electrochemical means.
In recent years, particularly, such sample analysis devices not only are used in hospitals, examination laboratories, etc., but also are applied in the remote diagnosis system whereby a patient him/herself collects a blood sample at home, and mails the collected sample held in the sample analysis device to a hospital so that tests are carried out on him/her without his/her going to the hospital. Further, a patient him/herself often carries out the sample analysis by using the sample analysis device through visual observation or by means of a simple measuring apparatus.
However, in such a case where the sample analysis device is handled by the patient him/herself who is not an expert, it is particularly important that the sample analysis device has excellent handlability. Therefore, for instance, a housed-type sample analysis device composed of a porous sheet as described above and a hollow plastic casing that houses the sheet therein is used widely at present, which is as disclosed in JP 7(1995)-46107 B.